Turbocharged and supercharged engines may be configured to compress ambient air entering the engine in order to increase power. Compression of the air may cause an increase in air temperature, thus, an intercooler or charge air cooler (CAC) may be utilized to cool the heated air thereby increasing its density and further increasing the potential power of the engine. Condensate may form in the CAC when the ambient air temperature decreases, or during humid or rainy weather conditions, where the intake air is cooled below the water dew point. Condensate (e.g., water droplets) may collect at the bottom of the CAC, or in the internal passages, and cooling turbulators. When torque is increased, such as during acceleration, increased mass air flow may strip the condensate from the CAC, drawing it into the engine and increasing the likelihood of engine misfire and combustion instability.
Other attempts to address engine misfire due to condensate ingestion involve avoiding condensate build-up. However, the inventors herein have recognized potential issues with such methods. Specifically, while some methods may reduce or slow condensate formation in the CAC, condensate may still build up over time. If this build-up cannot be stopped, ingestion of the condensate during acceleration may cause engine misfire. Another method to prevent engine misfire due to condensate ingestion includes trapping and/or draining the condensate from the CAC. While this may reduce condensate levels in the CAC, condensate is moved to an alternate location or reservoir, which may be subject to other condensate problems such as freezing and corrosion.
The inventors herein have recognized that under various pressure conditions charge air condensate may be stripped from the cooling tubes of the charge air cooler before excess condensation can build up if the air flow velocity through the CAC remains above a minimum threshold. Thus, in one example, the issues described above may be addressed by an air flow regulating element positioned in a tank of the CAC, the air flow regulating element adjustable to alter a number of cooling tubes in the CAC through which air flows. In one example, the air flow regulating element may include a cylindrical barrel valve rotatable about a rotational axis to adjust air flow through cooling tubes within the CAC. Specifically, the cooling tubes may include a first set of cooling tubes wherein air flow through the first set of cooling tubes is always flowing. The cooling tubes may further include a second set of cooling tubes wherein air flow through the second set of cooling tubes is regulated with the air flow regulating element. In an alternate embodiment, air flow through the first set of cooling tubes may also be regulated with the air flow regulating element and air flow may only be flowing through the first set of cooling tubes when air is not flowing through the second set of cooling tubes. A controller may rotate the barrel valve into different positions to increase or decrease an air flow velocity through the cooling tubes of the CAC. In some examples, the position of the barrel valve may be adjusted based on a mass air flow rate and/or a temperature at an outlet of the CAC.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.